Recent digital printing devices have made it possible to print pages which are completely different from one another. A page is typically described using a page description language (PDL) such as PostScript PDL and “PDF” by Adobe Systems, Inc., Mountain View, Calif. A PDL file typically includes a list of commands which, when interpreted, generate graphical objects such as text, images, etc. Variable data printing is a form of printing that produces individualized printed pages containing information that varies from instance to instance, each instance targeted, for example, to an individual recipient. With variable printing, each page can contain variable data with unrestricted variability from page to page.
Generally, existing tools for printing multi-page documents define each page as a collection of page elements where each page element is defined in PDL as part of a page description file. Each page element of a page is rasterized using a raster image processor to generate a bitmap image. The rasterization includes interpreting the objects defined in a PDL file and generating a set of images corresponding to the objects. Finally, the page elements are merged together into a larger image, typically during printing. In such architecture, the number of page elements in a page can vary from page to page. Therefore the time to generate each page and hence the print performance is unpredictable. Also, a color management system is usually applied to all page elements of a page before printing. In existing systems, a color management system is typically applied separately to different elements, e.g. to variable data regions and to fixed data regions. This can give undesirable results in areas where the different elements overlap each other after merging.
Thus, in printing pages with multiple page elements, there is a need for a method and an apparatus that improves the predictability of the time required to merge data for a page. There is also a need to be able to correctly apply color management to resolve issues that might occur in regions of overlapping page elements.